@Jo-Rien-Steenbergen If it's any consolation, I had a similar problem with Console after upgrade - not as severe as yours, it just stopped the Editor from working.
After a lot of digging and following blind alleys, I also found my problem fixed when I cleared my browser cache.
My suspicion is that there is something in the latest upgrade that is expecting data in a different format and that the Console code gets problems when it received cached browser data that is in the previous format - just my guess, but makes sense.

I think the Omega people should possibly look at this and if nothing can be done in the future, each upgrade should come with a warning that you may need to clear the browser cache